Cell-Only Population Challenges National Polls

This Brief is too brief to do justice to the detailed findings in the referenced study important to researchers in the marketing, merchandising and media fields. We strongly recommend that, if the subject of polling and data collection by phone is relevant, the reader might pursue the links to gain more insight into the charts and findings. (Ed.)

According to a Pew Research Center study, a growing number of Americans rely solely on a cell phone for their telephone service, and many more are considering giving up their landline phones. This trend presents a challenge to public opinion polling,

According to the U.S. Consumer Expenditure Survey, the percentage of households paying a cell phone bill but not a landline bill rose from 0.4% in 2000 to 7.8% in the first quarter of 2005. And, the National Health Interview Survey estimated that, in the second half of 2005, 7.8% of adults lived in households with only a cell phone. In the 2004 exit poll by the National Election Pool, 7.1% of voters said they relied solely on cell phones.

Recent research by the Pew Research Center, in conjunction with the Associated Press and AOL, was conducted to assess the challenge posed by cell phones to random digit dial surveys, which typically rely on a random sample of the population of landline subscribers. The study determined that the relatively small size of the cell-only group, along with the demographic weighting performed when it is combined with the landline sample, accounts for the minimal change in the overall findings.

Specifically, the study shows that including cell-only respondents with those interviewed from a standard landline sample, and weighting the resulting combined sample to the full U.S. public demographically, changes the overall results of the poll by no more than one percentage point on any of nine key political questions included in the study.

This, in spite of the fact that a new study of the issue finds that cell-only Americans, an estimated 7%-9% of the general public, are significantly different in many ways from those reachable on a landline. They are younger, less affluent, less likely to be married or to own their home, and more liberal on many political questions.

According to data collected by the National Center for Heath Statistics, 53% of Americans use both a landline and a cell phone; 37% have only a landline; and 8% rely only on a cell phone.

Like the cell-only population, Americans who rely solely on a landline are distinctive demographically. Fully 41% are ages 65 and older, compared with 16% of the general public. The landline-only group includes a greater proportion of whites than the general public (82% vs. 73%).

Among dual phone users, there are clear differences between those reached on a cell phone and those contacted on a landline. People who were interviewed on a cell phone are somewhat younger (24% under age 30 vs. 15% among those reached on a landline), more likely to be Hispanic (9% vs. 5%), and slightly more likely to have a child under 18 in the household (43% vs. 35%).